Studio preliminare sulle caratteristiche di impiego di una biochimosina nella produzione di formaggi molli

Cheese production is traditionally based on milk clotting by rennet enzymes, such as chymosin and pepsin, extracted from the calves’ abomasum. Recently, the traditional calf rennet is less and less available because the stomachs mainly come from older animals, and the commercial rennet appears to contain ever-increasing amounts of bovine pepsin. For these reasons, new calf rennet substitutes are being promoted as interesting alternative concerning their lower prices and technological properties. The aim of this work is to test the technological suitability of a new biochymosin in comparison with calf rennet in experimental soft cheese production. The features of the new Gist Brocades chymosin Maxiren (GB) have been evaluated in experimental cheesemaking tests and compared with a calf rennet (HA) as reference. A third rennet (MIX) with the same enzymatic composition of the calf rennet reference, but obtained by mixing opportunely GB chymosin and a bovine rennet, has also been tested to compare the effect of different chymosin origin. Parallel tests have been carried out for Mozzarella, Crescenza and Italico cheese on a pilot-scale production (about 100 lt milk each test). At different times during cheese-ripening the chemical-physical parameters and the free amino acid content have been detected. Moreover sensory tests and colour analysis of cheeses have been carried out. The experimental chymosin in normal practice doesn’t cause different states during cheesemaking steps; its technological behavior is quite similar to the traditional rennet. No particular modifications in texture, colour and taste of cheeses appear by using the new biochymosin. Slight differences with regards to cheese composition and organoleptic characters are probably due to the variability of pilot-scale productions. Regarding the free amino acid composition, only for Italico cheese the GB chymosin seems to have a lower proteolytic activity than rennets containing bovine pepsin.

La ricerca è stata condotta con lo scopo di verificare le caratteristiche di una biochimosina sostitutiva del caglio tradizionale di vitello, in caseificazioni sperimentali per la produzione di formaggi molli quali Mozzarella, Crescenza ed Italico. Nelle condizioni adottate il comportamento tecnologico del coagulante sperimentale Maxiren appare del tutto simile a quello del caglio di vitello. L’impiego della biochimosina non determina nel formaggio particolari modificazioni della struttura, nel colore e nel gusto. Anche le rese di produzione non si discostano rispetto alla norma. Alcune lievi differenze riscontrate nella composizione centesimale ed in particolare nel contenuto in amminoacidi liberi dei formaggi possono essere attribuite solo alla variabilità determinata da una produzione in scala pilota e non all’azione del coagulante di diversa origine.